(a) Field of the Invention
The present invention relates to the automatic sanitizing of flush toilets by means of dispensing certain water-soluble triphenylmethane dyestuffs and a sanitizing agent into the toilet bowl with each flush. The dyestuff is resistant to attack by the sanitizing agent and thus, provides color to the bowl water during the time period that the water remains in the bowl between flushes.
(b) Information Disclosure Statement
Automatically dispensed toilet bowl cleaning and/or sanitizing systems which contain colorants to provide a visual signal to the user that the sanitizing product is being dispensed are well known. There are two general types of these sanitizing systems available. One of these systems has a visual signal which is transitory, that is, the sanitizing solution in the toilet bowl retains its colored appearance for only a brief amount of time. The other system, and one in which this invention finds its utility, is the system wherein the sanitizing solution in the toilet bowl is intended to show persistent color until the next flush.
U.S. Pat. No. 3,504,384, which issued Apr. 7, 1970, discloses that the dyestuff known as Disulfide Blue VN150 can be incorporated into surfactant components contained within a dual compartment dispenser for automatically dispensing a hypochlorite solution and a surfactant solution into the toilet bowl during flushing. This dye, which is believed to be Disulphine Blue VN150 (Color Index 42045) having the formula ##STR1## has been found to be resistant to oxidation to a colorless state by hypochlorite. But, solutions of this dye have a tendency to change from a blue shade to a reddish-purple shade upon prolonged contact with hypochlorite.
U.S. Pat. No. 4,200,606, which issued Apr. 29, 1980, discloses a method of treating a flush toilet, from a dual compartment dispenser for automatically dispensing, with a hypochlorite sanitizing solution and a surfactant solution each time the toilet is flushed. A persistent color is purportedly maintained in the bowl water by incorporating either FD&C Blue No. 1 having the formula ##STR2## or FD&C Green No. 3 having the formula ##STR3## into the surfactant solution.
U.S. Pat. No. 4,248,827, which issued Feb. 3, 1981, discloses a method of treating a flush toilet each time it is flushed with a bromide-catalyzed hypochlorite sanitizing solution and a surfactant solution from a dual compartment dispenser for automatically dispensing the solution. A transitory visual signal is provided to indicate the activity of the sanitizing agent in the bowl by incorporating a dye selected from the group of those identified by the Color Index numbers 24401; 42040; 63010; 42085; 42675; and those having Color Index names Basic Blue 80, Reactive Blue 17 and Acid Blue 182 into the surfactant solution.
U.S. Pat. No. 3,545,014, which issued Dec. 8, 1970, discloses an automatic sanitizer for flush toilets which contains a blue dye known as Acid Blue 9 (Color Index 42090) stated to impart a blue color to the water in the bowl.
The most common sanitizing agent used in automatic toilet bowl sanitizers is a chemical compound which will generate hypochlorite ion in water. The hypochlorite ion is a strong oxidizing agent which makes it highly effective in bleaching stains, breaking down and removing soils and killing microorganisms, thereby providing effective sanitizing action to the toilet bowl. Although highly effective in bleaching stains, removing soil and killing microorganisms thereby providing effective sanitizing action in the toilet bowl, hypochlorite ion will also operate to bleach or oxidize any dye which is utilized as a colorant in the automatic toilet bowl sanitizers. In any toilet bowl sanitizing system which is designed to provide a persistent visual signal between flushes, which period is often up to six to eight hours or longer, any such system requires a dye which is resistant to attack by oxidizing agents such as hypochlorite and which will not be bleached to a colorless state or oxidized to a different and aesthetically displeasing shade or color. Currently known automatic toilet bowl sanitizers have been only partially successful in this regard and accordingly there is a need for an automatic toilet bowl sanitizing system which provides a stable visual color signal which persists for between six to eight hours between flushings.